Corrosion-resistant powder coating for container and preparation method thereof

Abstract

The invention relates to the technical field of powder coatings, in particular to a corrosion-resistant powder coating for a container and a preparation method of the corrosion-resistant powder coating. The corrosion-resistant powder coating for the container, provided by the invention, comprises the following raw materials in parts by weight: 20-40 parts of carboxyl polyester resin; 20 to 30 parts of bisphenol A epoxy resin; 5 to 10 parts of single-layer graphene oxide; and 0.01 to 0.05 part of subphyllin. 3-6 parts of a curing agent; 10 to 25 parts of filler; and 1-3 parts of an auxiliary agent. The corrosion-resistant powder coating for the container, provided by the invention, not only can prevent the container from being corroded, but also can prolong the corrosion-resistant time of the container, and meanwhile, the powder coating also can improve the adhesive force between the powder coating and a base material.

Description

Technical Field

[0001] The invention relates to the technical field of powder coatings, and in particular to a corrosion-resistant powder coating for containers and a preparation method thereof. Background Art

[0002] Most containers are made of steel. Although steel has high strength and toughness and can withstand various mechanical loads during the transportation of containers, such as stacking pressure and tension during lifting, steel itself is more susceptible to corrosion in the natural environment. The main component of steel is iron, which has active chemical properties. In the presence of oxygen and water, electrochemical corrosion will occur. The basic chemical reaction process is: iron atoms lose electrons to become ferrous ions, oxygen gains electrons in the presence of water and reacts with water to form hydroxide ions, and ferrous ions further react with hydroxide ions to form ferrous hydroxide. Ferrous hydroxide is unstable and will be oxidized to ferric hydroxide, and finally decompose to form rust. This corrosion process will gradually weaken the structural strength of the container.

[0003] To this end, people have come up with many ways to prevent containers from corrosion, such as: using suitable organic solvents (such as gasoline, kerosene, trichloroethylene, etc.) or alkaline degreasers to remove oil stains on the surface of the container, then using mechanical or chemical rust removal, and finally phosphating or passivating the surface of the container; using suitable primers, topcoats, etc., to apply on the surface of the container; spraying corrosion-resistant powder coatings on the surface of the container.

[0004] However, the existing corrosion-resistant powder coatings have a relatively short protection time for containers, and their bonding performance with the substrate is poor and the adhesion is not high. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a corrosion-resistant powder coating for containers and a preparation method thereof. The powder coating prevents corrosion of the container and can also extend the corrosion resistance time of the container. At the same time, the powder coating can also improve its adhesion to the substrate.

[0006] To this end, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a corrosion-resistant powder coating for containers in an optional embodiment, comprising the following raw materials in parts by weight: 20-40 parts of carboxyl polyester resin; 20-30 parts of bisphenol A epoxy resin; 5-10 parts of monolayer graphene oxide; 0.01-0.05 parts of phylloxetine; 3-6 parts of curing agent; 10-25 parts of filler; and 1-3 parts of auxiliary agent.

[0008] In the present invention, globulin and monolayer graphene oxide can cooperate with each other to form a more compact, continuous and stable protective film on the metal surface of the container. Globulin can fill the tiny gaps between graphene oxide sheets, making the structure of the protective film more compact and further reducing the penetration channel of the corrosive medium. Globulin can be attached to the metal surface by chemical bonding, physical adsorption and other methods. Graphene oxide interacts with the metal surface by relying on its surface functional groups. The two work together to greatly enhance the adhesion between the protective film and the metal matrix, making it less likely to fall off or be damaged in harsh marine environments or complex conditions of use, thereby effectively protecting the container metal from corrosion for a long time. Globulin affects the electrode potential of the metal surface, inhibits the anode and cathode reactions, and reduces the electrochemical corrosion rate. Monolayer graphene oxide further interferes with the formation and reaction process of the corrosion cell by virtue of its good conductivity and regulation of electron distribution. The two work together to more effectively inhibit the metal loss caused by electrochemical corrosion during the use of the container, and significantly improve its corrosion resistance. Carboxyl polyester resin and bisphenol A epoxy resin undergo cross-linking reaction under the action of curing agent to form an interpenetrating network structure. This structure makes the coating denser, reduces pores and defects, and greatly reduces the possibility of corrosive substances (such as water, oxygen, salt ions, etc.) penetrating into the surface of the container, thereby improving the corrosion resistance. Monolayer graphene oxide has a two-dimensional flaky structure, which can be evenly dispersed in the coating and form a stacked physical barrier. It can effectively extend the diffusion path of corrosive substances in the coating, further prevent them from reaching the surface of the container, enhance the overall protection effect, and improve the corrosion resistance. The carboxyl group in the carboxyl polyester resin and the polar groups such as hydroxyl, ether and epoxy groups in the bisphenol A epoxy resin can react chemically with the metal oxide on the surface of the container to form chemical bonds. At the same time, the functional groups such as hydroxyl and carboxyl on the surface of the monolayer graphene oxide can also chemically bond with the surface of the container and the resin, thereby significantly improving the adhesion of the coating to the container. In addition, the monolayer graphene oxide has a certain conductivity and can form a conductive path in the coating. When local corrosion occurs on the surface of the container, graphene oxide can act as a sacrificial anode and react preferentially with the corrosive medium, thereby slowing down the corrosion rate of the container metal, playing a certain cathodic protection role, and further improving the corrosion resistance of the entire system.

[0009] Preferably, the acid value of the carboxyl polyester resin is 20-50 mgKOH / g; and / or, the epoxy equivalent of the bisphenol A epoxy resin is 180-200 g / eq. The curing agent is selected from one or more of triglycidyl isocyanurate or hydroxyalkylamide; and / or, the filler is selected from one or more of precipitated barium sulfate or talc.

[0010] Preferably, the auxiliary agent includes a leveling agent, a defoaming agent and a brightening agent;

[0011] The mass ratio of the leveling agent, the defoaming agent and the brightener is 0.5-1: 0.3-0.6: 0.2-0.5. The leveling agent is acrylate, the defoaming agent is polypropylene glycol, and the brightener is aluminum stearate. The acrylate is selected from methyl acrylate or ethyl acrylate, and the polypropylene glycol is polypropylene glycol 200.

[0012] Preferably, the corrosion-resistant powder coating for containers further comprises 10-20 parts of pigment; the raw materials are selected from one or more of titanium dioxide or red iron oxide.

[0013] Furthermore, the corrosion-resistant powder coating for containers includes the following raw materials in parts by weight: 30 parts of carboxyl polyester resin; 25 parts of bisphenol A epoxy resin; 8 parts of single-layer graphene oxide; 2 parts of triglycidyl isocyanurate; 15 parts of precipitated barium sulfate; 0.8 parts of acrylate; 0.4 parts of polypropylene glycol; 0.3 parts of aluminum stearate; and 7 parts of red iron oxide.

[0014] In a second aspect, the present invention provides, in an optional embodiment, a method for preparing the above-mentioned corrosion-resistant container powder coating, comprising the following steps:

[0015] S1: weighing raw materials according to weight, and premixing them to obtain a premix;

[0016] S2: extruding, granulating, crushing and screening the premix to obtain the corrosion-resistant container powder coating;

[0017] Wherein, the premix temperature is 40-80°C.

[0018] In the present invention, premixing at 40-80°C can make the resin and the curing agent fully contact and partially crosslink in advance, forming a more uniform and stable network structure. And some additives can better play their functions at high temperatures, thereby improving the corrosion resistance of the coating. For example, when the leveling agent is premixed at high temperature, it can more effectively reduce the surface tension of the coating, so that the coating can be better leveled during the curing process, and reduce the generation of surface defects such as pinholes and bubbles, etc., which are often channels for corrosive media to easily invade. Reducing defects also improves the corrosion resistance of the coating. And high-temperature premixing can volatilize the moisture and some low-boiling impurities in the premix. The presence of moisture may cause bubbles to form in the coating during the curing process, destroying the compactness of the coating, and may also trigger the hydrolysis reaction of the resin, reducing the performance and corrosion resistance of the coating. Removing impurities can reduce the adverse factors that may affect the quality and corrosion resistance of the coating, making the coating system purer, which is conducive to improving corrosion resistance. In the high-temperature premixing process, the resin and other components react chemically or physically adsorb with the active groups on the surface of the substrate at high temperature, thereby enhancing the bonding force between the coating and the substrate. Good adhesion can prevent the coating from falling off or peeling off due to external forces during use, allowing the coating to better play its protective role, thereby improving the protection of the substrate and indirectly improving corrosion resistance.

[0019] Preferably, in step S1, the premixing speed is 800-1200 r / min; and / or, the premixing time is 10-15 min. The extrusion granulation adopts a twin-screw extruder; in the twin-screw extruder, the temperature of zone 1 is 90-100°C, the temperature of zone 2 is 100-110°C, the temperature of zone 3 is 110-120°C, and the screw speed is 30-50 r / min.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The corrosion-resistant powder coating for containers provided by the present invention can not only prevent the container from corrosion, but also extend the corrosion-resistant time of the container. At the same time, the powder coating can also improve its adhesion to the substrate.

[0022] 2. The phylloxanthin and monolayer graphene oxide of the present invention can cooperate with each other to form a more compact, continuous and stable protective film on the metal surface of the container. The phylloxanthin can fill the tiny gaps between the graphene oxide sheets, making the structure of the protective film more compact and further reducing the penetration channels of the corrosive medium. The phylloxanthin can be attached to the metal surface by chemical bonding, physical adsorption and other methods. Graphene oxide interacts with the metal surface by relying on its surface functional groups. The two can work together to greatly enhance the adhesion between the protective film and the metal matrix, making it less likely to fall off or be damaged in harsh marine environments or complex conditions of use, thereby effectively protecting the container metal from corrosion for a long time. The phylloxanthin affects the electrode potential of the metal surface, inhibits the anode and cathode reactions, and reduces the electrochemical corrosion rate. The monolayer graphene oxide further interferes with the formation and reaction process of the corrosion cell by virtue of its good conductivity and regulation of electron distribution. The two work together to more effectively inhibit the metal loss caused by electrochemical corrosion during the use of the container, and significantly improve its corrosion resistance.

[0023] 3. The carboxyl polyester resin and bisphenol A epoxy resin of the present invention undergo a cross-linking reaction under the action of a curing agent to form an interpenetrating network structure. This structure makes the coating more compact, reduces pores and defects, and greatly reduces the possibility of corrosive substances (such as water, oxygen, salt ions, etc.) penetrating into the surface of the container, thereby improving the corrosion resistance. The monolayer graphene oxide has a two-dimensional flaky structure, which can be evenly dispersed in the coating and form a stacked physical barrier. It can effectively extend the diffusion path of corrosive substances in the coating, further prevent them from reaching the surface of the container, enhance the overall protective effect, and improve the corrosion resistance. The carboxyl group in the carboxyl polyester resin and the polar groups such as hydroxyl, ether and epoxy groups in the bisphenol A epoxy resin can react chemically with the metal oxide on the surface of the container to form a chemical bond. At the same time, the functional groups such as hydroxyl and carboxyl on the surface of the monolayer graphene oxide can also chemically bond with the surface of the container and the resin, thereby significantly improving the adhesion of the coating to the container. In addition, the monolayer graphene oxide has a certain conductivity and can form a conductive path in the coating. When local corrosion occurs on the surface of the container, graphene oxide can act as a sacrificial anode and react preferentially with the corrosive medium, thereby slowing down the corrosion rate of the container metal, playing a certain cathodic protection role, and further improving the corrosion resistance of the entire system.

[0024] 4. The premixing (40-80°C) of the present invention can make the resin and the curing agent fully contact and partially cross-link in advance, forming a more uniform and stable network structure. And some additives can better play their functions at high temperatures, thereby improving the corrosion resistance of the coating. For example, when the leveling agent is premixed at high temperature, it can more effectively reduce the surface tension of the coating, so that the coating can be better leveled during the curing process, and reduce the generation of surface defects such as pinholes and bubbles, etc., which are often channels for corrosive media to easily invade. Reducing defects also improves the corrosion resistance of the coating. In addition, high-temperature premixing can volatilize the moisture and some low-boiling impurities in the premix. The presence of moisture may cause bubbles to form in the coating during the curing process, destroying the compactness of the coating, and may also trigger the hydrolysis reaction of the resin, reducing the performance and corrosion resistance of the coating. Removing impurities can reduce the adverse factors that may affect the quality and corrosion resistance of the coating, making the coating system purer, which is conducive to improving corrosion resistance. During the high-temperature premixing process, the resin and other components react chemically or physically adsorb with the active groups on the surface of the substrate at high temperature, thereby enhancing the bonding force between the coating and the substrate. Good adhesion can prevent the coating from falling off or peeling off due to external forces during use, allowing the coating to better play its protective role, thereby improving the protection of the substrate and indirectly improving corrosion resistance. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] In the following examples and comparative examples, carboxyl polyester resin was purchased from Jiangsu Best New Materials Co., Ltd., model number YZ9820Q; bisphenol A epoxy resin was purchased from Shandong Deyuan Epoxy Technology Co., Ltd., model number DY-128E; single-layer graphene oxide was purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model number XF002-2; phyllotoxin was purchased from Sichuan Weikeqi Biotechnology Co., Ltd., model number WKQ-0003301.

[0027] The technical solution of the present invention will be described below in conjunction with embodiments.

[0028] Example 1

[0029] The present embodiment provides a corrosion-resistant powder coating for containers, including 30g of carboxyl polyester resin, 25g of bisphenol A epoxy resin, 8g of single-layer graphene oxide, 0.03g of phyllotoxin, 2g of triglycidyl isocyanurate, 15g of precipitated barium sulfate, 0.8g of methyl acrylate, 0.4g of polypropylene glycol 200, 0.3g of aluminum stearate and 7g of red iron oxide.

[0030] The method for preparing the above-mentioned corrosion-resistant container powder coating comprises the following steps:

[0031] S1: weigh the raw materials according to the above weight, add them into a high-speed mixer, and premix them for 15 minutes at a temperature of 60° C. and a rotation speed of 1000 r / min to obtain a premix;

[0032] S2: The premix is ​​granulated in a twin-screw extruder, wherein the temperature of the first zone of the twin-screw extruder is set to 90-100°C, the temperature of the second zone is set to 100-110°C, the temperature of the third zone is set to 110-120°C, and the speed of the screw is 40r / min. During the extrusion process, the material is pushed by the screw and passes through the high-temperature area, so that the resin is fully melted and evenly mixed with other ingredients. After extrusion through the die head, it forms a strip-shaped material, and then cuts into uniform particles by a pelletizer. The particles after extrusion granulation are crushed by a pulverizer to obtain a powder coating. The crushed powder coating is sieved by a sieving machine, and the mesh number of the sieve is 200 meshes to obtain a corrosion-resistant powder coating for containers.

[0033] Example 2

[0034] The present embodiment provides a corrosion-resistant powder coating for containers, including 20g of carboxyl polyester resin, 30g of bisphenol A epoxy resin, 5g of single-layer graphene oxide, 0.05g of phyllotoxin, 6g of triglycidyl isocyanurate, 10g of precipitated barium sulfate, 2g of methyl acrylate, 0.6g of polypropylene glycol 200, 0.4g of aluminum stearate and 10g of red iron oxide.

[0035] The preparation method of the above-mentioned corrosion-resistant powder coating for containers is the same as that of Example 1.

[0036] Example 3

[0037] The present embodiment provides a corrosion-resistant powder coating for containers, including 40g of carboxyl polyester resin, 20g of bisphenol A epoxy resin, 10g of single-layer graphene oxide, 0.01g of phyllotoxin, 3g of triglycidyl isocyanurate, 25g of precipitated barium sulfate, 0.5g of methyl acrylate, 0.3g of polypropylene glycol 200, 0.2g of aluminum stearate and 20g of red iron oxide.

[0038] The preparation method of the above-mentioned corrosion-resistant powder coating for containers is the same as that of Example 1.

[0039] Example 4

[0040] The present embodiment provides a corrosion-resistant powder coating for containers, including 30g of carboxyl polyester resin, 25g of bisphenol A epoxy resin, 8g of single-layer graphene oxide, 0.03g of phyllotoxin, 2g of triglycidyl isocyanurate, 15g of precipitated barium sulfate, 0.8g of methyl acrylate, 0.4g of polypropylene glycol 200, 0.3g of aluminum stearate and 7g of red iron oxide.

[0041] The method for preparing the above-mentioned corrosion-resistant container powder coating comprises the following steps:

[0042] S1: weigh the raw materials according to the above weight, add them into a high-speed mixer, and premix them for 15 minutes at a temperature of 40° C. and a rotation speed of 1000 r / min to obtain a premix;

[0043] S2: The premix is ​​granulated in a twin-screw extruder, wherein the temperature of the first zone of the twin-screw extruder is set to 90-100°C, the temperature of the second zone is set to 100-110°C, the temperature of the third zone is set to 110-120°C, and the speed of the screw is 40r / min. During the extrusion process, the material is pushed by the screw and passes through the high-temperature area, so that the resin is fully melted and evenly mixed with other ingredients. After extrusion through the die head, it forms a strip-shaped material, and then cuts into uniform particles by a pelletizer. The particles after extrusion granulation are crushed by a pulverizer to obtain a powder coating. The crushed powder coating is sieved by a sieving machine, and the mesh number of the sieve is 200 meshes to obtain a corrosion-resistant powder coating for containers.

[0044] Example 5

[0045] The present embodiment provides a corrosion-resistant powder coating for containers, including 30g of carboxyl polyester resin, 25g of bisphenol A epoxy resin, 8g of single-layer graphene oxide, 0.03g of phyllotoxin, 2g of triglycidyl isocyanurate, 15g of precipitated barium sulfate, 0.8g of methyl acrylate, 0.4g of polypropylene glycol 200, 0.3g of aluminum stearate and 7g of red iron oxide.

[0046] The method for preparing the above-mentioned corrosion-resistant container powder coating comprises the following steps:

[0047] S1: weigh the raw materials according to the above weight, add them into a high-speed mixer, and premix them for 15 minutes at a temperature of 80° C. and a rotation speed of 1000 r / min to obtain a premix;

[0048] S2: The premix is ​​granulated in a twin-screw extruder, wherein the temperature of the first zone of the twin-screw extruder is set to 90-100°C, the temperature of the second zone is set to 100-110°C, the temperature of the third zone is set to 110-120°C, and the speed of the screw is 40r / min. During the extrusion process, the material is pushed by the screw and passes through the high-temperature area, so that the resin is fully melted and evenly mixed with other ingredients. After extrusion through the die head, it forms a strip-shaped material, and then cuts into uniform particles by a pelletizer. The particles after extrusion granulation are crushed by a pulverizer to obtain a powder coating. The crushed powder coating is sieved by a sieving machine, and the mesh number of the sieve is 200 meshes to obtain a corrosion-resistant powder coating for containers.

[0049] Comparative Example 1

[0050] The comparative example provides a corrosion-resistant powder coating for containers, comprising 30 g of carboxyl polyester resin, 25 g of bisphenol A epoxy resin, 0.03 g of phyllotoxin, 2 g of triglycidyl isocyanurate, 15 g of precipitated barium sulfate, 0.8 g of methyl acrylate, 0.4 g of polypropylene glycol 200, 0.3 g of aluminum stearate and 7 g of red iron oxide.

[0051] The preparation method of the above-mentioned corrosion-resistant powder coating for containers is the same as that of Example 1.

[0052] Comparative Example 2

[0053] The comparative example provides a corrosion-resistant powder coating for containers, comprising 30 g of carboxyl polyester resin, 25 g of bisphenol A epoxy resin, 8 g of monolayer graphene oxide, 2 g of triglycidyl isocyanurate, 15 g of precipitated barium sulfate, 0.8 g of methyl acrylate, 0.4 g of polypropylene glycol 200, 0.3 g of aluminum stearate and 7 g of red iron oxide.

[0054] The preparation method of the above-mentioned corrosion-resistant powder coating for containers is the same as that of Example 1.

[0055] Comparative Example 3

[0056] The comparative example provides a corrosion-resistant powder coating for containers, comprising 55 g of bisphenol A epoxy resin, 8 g of monolayer graphene oxide, 0.03 g of phyllotoxin, 2 g of triglycidyl isocyanurate, 15 g of precipitated barium sulfate, 0.8 g of methyl acrylate, 0.4 g of polypropylene glycol 200, 0.3 g of aluminum stearate and 7 g of red iron oxide.

[0057] The preparation method of the above-mentioned corrosion-resistant powder coating for containers is the same as that of Example 1.

[0058] Comparative Example 4

[0059] The comparative example provides a corrosion-resistant powder coating for containers, comprising 55 g of carboxyl polyester resin, 8 g of monolayer graphene oxide, 0.03 g of phyllotoxin, 2 g of triglycidyl isocyanurate, 15 g of precipitated barium sulfate, 0.8 g of methyl acrylate, 0.4 g of polypropylene glycol 200, 0.3 g of aluminum stearate and 7 g of red iron oxide.

[0060] The preparation method of the above-mentioned corrosion-resistant powder coating for containers is the same as that of Example 1.

[0061] Comparative Example 5

[0062] The comparative example provides a corrosion-resistant powder coating for containers, comprising 30 g of carboxyl polyester resin, 25 g of bisphenol A epoxy resin, 8 g of monolayer graphene oxide, 0.03 g of phyllotoxin, 2 g of triglycidyl isocyanurate, 15 g of precipitated barium sulfate, 0.8 g of methyl acrylate, 0.4 g of polypropylene glycol 200, 0.3 g of aluminum stearate and 7 g of red iron oxide.

[0063] The method for preparing the above-mentioned corrosion-resistant container powder coating comprises the following steps:

[0064] S1: weigh the raw materials according to the above weight, add them into a high-speed mixer, and premix them for 15 minutes at room temperature (temperature is 25° C.) and a rotation speed of 1000 r / min to obtain a premix;

[0065] S2: The premix is ​​granulated in a twin-screw extruder, wherein the temperature of the first zone of the twin-screw extruder is set to 90-100°C, the temperature of the second zone is set to 100-110°C, the temperature of the third zone is set to 110-120°C, and the speed of the screw is 40r / min. During the extrusion process, the material is pushed by the screw and passes through the high-temperature area, so that the resin is fully melted and evenly mixed with other ingredients. After extrusion through the die head, it forms a strip-shaped material, and then cuts into uniform particles by a pelletizer. The particles after extrusion granulation are crushed by a pulverizer to obtain a powder coating. The crushed powder coating is sieved by a sieving machine, and the mesh number of the sieve is 200 meshes to obtain a corrosion-resistant powder coating for containers.

[0066] Experimental example

[0067] The corrosion-resistant powder coatings for containers prepared in Examples 1-5 and Comparative Examples 1-5 were sprayed onto the surface of the container using an electrostatic spraying technique with a spraying thickness of 3 mm, and then subjected to corrosion resistance performance tests and adhesion performance tests.

[0068] The method for testing the corrosion resistance performance is: place the spray coating under a 300W ultraviolet lamp for 12 hours (ambient temperature is 40°C, relative humidity is 80% RH), then place it in a dark environment for 12 hours, and observe the number of days for spots to appear on the spray coating.

[0069] The method for testing adhesion performance is: using a puller to test.

[0070] The test results are shown in Table 1.

[0071] Table 1 Corrosion resistance performance test and adhesion performance test results of the spray coating

[0072] Days since spots appeared (d) Adhesion(MPa) Example 1 186 60 Example 2 171 55 Example 3 168 58 Example 4 177 59 Example 5 174 59 Comparative Example 1 82 27 Comparative Example 2 78 26 Comparative Example 3 103 35 Comparative Example 4 114 34 Comparative Example 5 145 46

[0073] Conclusion: By comparing the data of Example 1 and Comparative Examples 1-4, it can be seen that the corrosion resistance and adhesion of the corrosion-resistant container powder coating prepared in Example 1 are significantly better than those of Comparative Examples 1-3. It can be seen that carboxyl polyester resin, bisphenol A epoxy resin, monolayer graphene oxide and phyllotoxin have a synergistic effect in improving the corrosion resistance and adhesion of container powder coatings. By comparing the data of Example 1 and Comparative Example 5, it can be seen that the corrosion resistance and adhesion of the corrosion-resistant container powder coating prepared in Example 1 are significantly better than those of Comparative Example 5. It can be seen that when premixing, increasing the premixing temperature can further improve the corrosion resistance and adhesion of the container powder coating.

[0074] Although the principles of the present invention are described in detail above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that the above embodiments are merely explanations of the exemplary implementations of the present invention, and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute limitations on the scope of the present invention, and any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, fall within the protection scope of the present invention.

Claims

1. A corrosion-resistant powder coating for containers, characterized in that: The invention comprises the following raw materials in parts by weight: 20-40 parts of carboxyl polyester resin; 20-30 parts of bisphenol A epoxy resin; 5-10 parts of monolayer graphene oxide; 0.01-0.05 parts of lipase under the leaves; 3-6 parts of curing agent; 10-25 parts of filler; 1-3 parts of additives.

2. The corrosion-resistant powder coating for containers according to claim 1, characterized in that: The acid value of the carboxyl polyester resin is 20-50 mgKOH / g; and / or, The epoxy equivalent of the bisphenol A epoxy resin is 180-200 g / eq.

3. The corrosion-resistant powder coating for containers according to claim 1, characterized in that: The curing agent is selected from one or more of triglycidyl isocyanurate or hydroxyalkylamide; and / or, The filler is selected from one or more of precipitated barium sulfate and talc.

4. The corrosion-resistant powder coating for containers according to claim 1, characterized in that: The auxiliary agents include leveling agents, defoaming agents and brightening agents; The mass ratio of the leveling agent, the defoaming agent and the brightening agent is 0.5-1:0.3-0.6:0.2-0.

5.

5. The corrosion-resistant powder coating for containers according to claim 4, characterized in that: The leveling agent is acrylate, the defoaming agent is polypropylene glycol, and the brightening agent is aluminum stearate.

6. The corrosion-resistant container powder coating according to claim 1, characterized in that: The corrosion-resistant container powder coating also includes 10-20 parts of pigment; The raw material is selected from one or more of titanium dioxide and red iron oxide.

7. A corrosion-resistant powder coating for containers according to any one of claims 1 to 6, characterized in that: The composition comprises the following raw materials in parts by weight: 30 parts of carboxyl polyester resin; 25 parts of bisphenol A epoxy resin; 8 parts of monolayer graphene oxide; 0.03 parts of lipase; 2 parts of triglycidyl isocyanurate; Precipitate barium sulfate 15 parts; Acrylate 0.8 part; 0.4 parts of polypropylene glycol; 0.3 parts of aluminum stearate; 7 parts of red iron oxide.

8. A method for preparing the corrosion-resistant powder coating for containers according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: weighing raw materials according to weight, and premixing them to obtain a premix; S2: extruding, granulating, crushing and screening the premix to obtain the corrosion-resistant container powder coating; Wherein, the premix temperature is 40-80°C.

9. The method for preparing the corrosion-resistant powder coating for containers according to claim 8, characterized in that: In step S1, the premixing speed is 800-1200 r / min; and / or, The premixing time is 10-15 minutes.

10. The method for preparing the corrosion-resistant powder coating for containers according to claim 8, characterized in that: The extrusion granulation adopts a twin-screw extruder; In the twin-screw extruder, the temperature of zone 1 is 90-100° C., the temperature of zone 2 is 100-110° C., the temperature of zone 3 is 110-120° C., and the rotation speed of the screw is 30-50 r / min.